Multi channel data transfer has been described in patents issued to Giorgio (U.S. Pat. Nos. 4,862,456 and 4,864,567) and to Nash (U.S. Pat. No. 4,577,312). However, these patents either use a central office switch or similar system to obtain simultaneous transmission which requires additional equipment and expense or do not comprise compression of data or multi tasking capabilities thereby limiting the over all throughput of data. Further none of these systems use a rule-based approach to the file management associated with transmission of large amounts of data.
In contrast, the present invention does not suffer from any of these restrictions. The present invention does not require any additional equipment beyond a normal computer with communication channels and modems. Further the present invention employs compression algorithms to further speed the transmission of data and executes in a multi-tasking environment to give further throughput of information. These factors, together with the use of a rule-based system of file management and channel selection renders the current invention extremely fast and easy to use, with a minimum of operator interaction.
Data files are read from the directory of a computer and analyzed as to their data content, format and category (i.e. binary, ASCII text, image format, etc.). Individual files or parts of individual files are then directed to any number of attached modems and their respective dial-up circuits. Data files are received at the remote end, and if segmented, re-appended (reconstructed) and stored on the remote end disk system component of a computer which is also equipped with multiple modems and multiple dial-up circuits. Individual line speeds exceed 60 kbps (6,000 characters per second) while aggregate baud rates (data throughput rates) are only limited by the number of lines and modems available for transmission.
U.S. Pat. No. 4,311,877 to Kahn discloses a method and means for improving the reliability of systems that transmit relatively wideband signals over two or more relatively narrowband transmission circuits. This invention divides the transmission line into separate lines, each carrying a different frequency range component of the overall frequency range carried on the original transmission line. The system also segments input signals according to frequency range, splitting the bandwidth of the original signal into frequency range components for transmission on the transmission lines. All input signals are segmented in the same manner so that they are passed by the matching line, thereby conserving bandwidth for the transmission. The present invention segments data files according to file size, not frequency range, in order to increase the overall throughput of the transmission. The segmentation performed by the present invention is based on rules for efficient transmission, not on a fixed set of frequency ranges.
Failures in a transmission circuit are detected by the Kahn invention. When a failure is found, a switching circuit is activated and the signal on that line is switched to a new line having the same bandwidth. However, only complete failures in the transmission circuit are detected by the Kahn invention. The present invention checks the signal to noise ratio of each transmission channel, switching channels if line degradation occurs.
In the Integrated Services Digital Network (ISDN) embodiment, utilizing 64 KBps or faster channels, individual data rates exceed 300 KBPS while aggregate data throughput is only limited by the number of ISDN circuits (and associated ISDN interfaces) available at both ends of the transmission system.
The system utilizes a novel file naming convention which enables the computer hardware and software to optimize data compression and/or file segmentation in order to achieve maximum data throughput. Destination address (telephone number) data are automatically computed based upon unique data file suffix interpretation.
A user friendly software front-end system is provided to automatically configure the system to the individual requirements of the user.
Data throughput rates are achieved which were hitherto only accomplished utilizing expensive leased data circuits operating at data rates of from 4800 to 56 KBPS or higher or other non-switched dedicated services. The system also facilitates switching of data which is not normally possible when leased lines (i.e., point to point) are utilized.
It is therefore an objective of the present invention to employ an expert system/rule-based approach to data transmission to minimize operator interaction in such data transmission, yet maximize the speed of transmission of data files of any type.
It is another objective of the present invention to provide a cost effective system of data transmission that is similar in performance to more expensive leased lines or dedicated higher capacity data transmission lines but which relies upon the use of low-cost communications channels such as dial-up service.
It is another objective of the present invention to further reduce communications costs by conducting as much file related manipulation as possible off line.
It is yet another objective of the present invention to provide a low cost replacement for more sophisticated and expensive data transmission controllers such as the IBM 3725 or 3705, or similar communications front end systems.
Further it is an objective of the present invention to provide rapid data communication in both foreign and domestic ISDN standard environments.